Umbrella base



FIG. 1 is a top plan view of an umbrella base showing my new design;

FIG. 2 is a front elevational view thereof, the rear elevational viewbeing identical thereto;

FIG. 3 is a right side elevational view thereof, the left side viewbeing identical thereto;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a vertical sectional view thereof, taken along line 5--5 ofFIG. 1; and

FIG. 6 is a vertical sectional view thereof, taken along line 6--6 ofFIG. 4.

The ornamental design for an umbrella base, as shown and described.